11 



the root of the plant, and, by its action, produced 

 stores of food, not only for ita host plant to flourish, 

 but without which the host plant could not live. 

 There they had the beneficial root parasite. The 

 lecturer said he desired to emphasise one particu- 

 lar constituent of plant food which the parasite 

 prepared. For a good many years fanciful theories 

 had been advanced as to how plants lived, but 

 recent researches all pointed to the cardinal fact 

 that plants derived their carbon, the most im- 

 portant element of their strut'iture, from the car- 

 bonic acid g'as which they found in the atmosphere. 

 It took a very long time to establish that fact. 

 There was one fact which was absolutely fixed, 

 viz . that no animal or plant could exist without 

 sufficient supplies of nitrogen. Let them feed a 

 man, for example, on butter, or salt, or starch, and 

 nitrogen starvation would follo^v. Without nitro- 

 gen no diet, whether animal or plant, was com- 

 plete. Professor Dunstan proceeded lo deal with 

 the hypothesis that plants gathered their nitrogen 

 from their leavep,and remarked that that idea had 

 again been started within the last few weeks by a 

 Scotch scientist, who put forward the theory that 

 there were certain tentacles on the leaves of 

 certain plants, which enabled those plants to lay 

 hold of the nitrogen of the air and utilize it for 

 their own purposes. He bhought, however, they 

 might take it that the assimilation of nitrogen by 

 means of the leaves was far from being a 

 proved fact. Where then did the nitrogen come 

 from ? Virgil noticed the fact that if they planted 

 a crop of beans or peas, and followed that crop 

 with wheat, that they got a very much better crop 

 than if they planted wheat or barley and followed 

 them with wheat or barley. So it was generally — 

 if they followed a leguminous crop with a corn 

 crop they got a much better crop than if they fol- 

 lowed a corn crop with a corn crop, because legu- 

 minous crops accumulated nitrogen in the ground. 

 That led scientists to tbink was there not some- 

 thing in the Ipguminous plant which had some 

 different function to other plants which could 



work upon the stores of nitrogen in the air in a 

 different way than other plants did. For 1,800 

 years farmers knew that wheat did best 

 after leguminous crops, but scientists were not 

 aware of the reason of that fact until the 

 last half of the last century. The lecturer 

 showed by illustration the growth of two pots 

 filled with sand, containing clover seed, which 

 bad all the necessary constituents except nitrogen. 

 The plants showed the effect of the nitrogen 

 starvation when they were about two inches high, 

 but when some garden soil extract was added to 

 one of the pots, the plant suddenly took a new 

 lease of life, and continued to grow in a healthy 

 way. If they subsequently took out the plants 

 and looked at their roots, they would s*^e on the 

 one, the ordinary plant root, but on the one to 

 which the garden soil extract had been added, 

 they would find little nodules, little excrescences, 

 and these excrescences were the secret of the 

 growth of the plant ; because in those excrescences 

 were bacteria, and those bacteria were what he 

 called the beneficial root parasite, which had the 

 power of taking nitrogen from the air and 

 converting it into the food upon which the plant 

 partly lived. So that the phenomenon of those 

 beneficial parasites was to make or manufacture for 

 the plant, the supply of nitrogenous food, without 

 which the plant could not exist ; for although there 

 was a sufficiency of that Iplant food in the air 

 around it, the plant could not extract it from the 

 air without the aid of those beneficial parasites. 

 In concluding. Professor Dunstan explained the 

 methods by which a farmer might derive the 

 greatest advantages by the scientific treatment of 

 his crops. 



The lecture was illustrated by means of numer- 

 ous lantern slides, Mr. Lander manipulating hla 

 new and compact form of electric lantern. 



At the close a very hearty vote of thanks was 

 accorded the lecturer, proposed by Mr. W. H. 

 Hammond and seconded by Mr. Page. 



SIXTH WINTER MEETING.— FEBRUARY 27th, 1906, 



•'COLOUR PHOTOGRAPHY, ETC., IN CARBON."— By ROTARY PHOTO CO. 



Owing to the serious illness of Mrs. McDakin, 

 the lecture by Captain McDakin arranged for Feb. 

 13th was postponed, and before the next meeting, 

 which was held on Tuesday, Feb. 27th, with much 

 regret we had to record her death, which took 

 place, after a short illness, at her residence 

 at Dover, at the age of 75 years. The Presi- 

 dent (Mr, Sidney Harvey) before commencing 

 the business, called attention to the fact that one 

 of their most prominent and useful members 

 (Capt. J. Gordon McDakin, of Dover) bad recently 

 undergone a very sad bereavement in the loss of 

 his wife. Mrs. McDakin had always ably assisted 

 her husband in bis studies, and the members of 

 the Society would remember her kind hospitality 



and how excellently she bad executed sketches 

 and diagrams for the Captain's lectures. The 

 President moved that a vote of sympathy and 

 condolence be eent to Captain McDakin, and this 

 was carried unanimonsly. 



The representative of the Rotary Photo Co. 

 then gave a very interesting demonstration of the 

 Rotox gaslight paper and bromide paper and satin 

 made by their company. He also described and 

 df'monstrated their system of colour photography 

 with the new tricolour carbon tissues. The lecture 

 was listened to with great attention, and a very 

 instructive and interesting evening was spent by 

 the members. 



